1. Field of the Invention
Present invention relates to an image processing apparatus having a plurality of resolutions.
2. Description of Related Art
Conventional image processing apparatuses, having a function for rotating information stored in a memory by a right angle (hereinafter referred to as "90.degree. rotation function"), read an image in a mode specified from an operation unit and store the read image data into the memory. Such reading modes are usually called "normal mode", "fine mode" and "super-fine mode". The resolution of the normal mode is 8 pel/mm.times.3.85 line/mm; that of the fine mode, 8 pel/mm.times.7.7 line/mm; and that of the super-fine mode, 8 pel/mm.times.15.41 line/mm (pel/mm: density in main-scanning direction; line/mm: density in subscanning direction).
When the conventional apparatus reads an image in the normal mode, it stores the read image data having 8 pel/mm.times.3.85 line/mm resolution into a memory. Problems is that if a 90.degree. rotation is performed on the stored image data, the line density of the rotated data in the main-scanning direction is degraded to 3.85 pel/mm. The conventional art converts the degraded line density into 8 pel/mm so as to raise the resolution, however, deterioration of image quality cannot be avoided.